Apparatus and method for improved ion beam current

Abstract

An apparatus may include an electrode system, the electrode system comprising a plurality of electrodes to guide an ion beam from an entrance aperture to an exit aperture, and a voltage supply to apply a plurality of voltages to the electrode system. The electrode system may comprise an exit electrode assembly, where the exit electrode assembly includes a first exit electrode and a second exit electrode, separated from the first exit electrode by an electrode gap. The first exit electrode and the second exit electrode may be movable with respect to one another so as to change a size of the electrode gap over a gap range.

The invention claimed is: 
     
       1. An apparatus, comprising:
 an electrode system, the electrode system comprising a plurality of electrodes to guide an ion beam from an entrance aperture to an exit aperture; and 
 a voltage supply to apply a plurality of voltages to the electrode system, 
 wherein the electrode system comprises an exit electrode assembly, the exit electrode assembly comprising a first exit electrode and a second exit electrode, separated from the first exit electrode by an electrode gap, wherein the first exit electrode and the second exit electrode are movable with respect to one another so as to change a size of the electrode gap over a gap range. 
 
     
     
       2. The apparatus of  claim 1 , further comprising a motor, the motor being mechanically coupled to the exit electrode assembly and supplying a linear motion to the exit electrode assembly. 
     
     
       3. The apparatus of  claim 1 , further comprising a controller to supply a control signal to adjust the electrode gap, responsive to user input. 
     
     
       4. The apparatus of  claim 1 , wherein the first exit electrode and the second exit electrode comprising a shaft, wherein the shaft comprises a shaft center, and wherein the shaft is rotatable about a rotation axis, the rotation axis being displaced from the shaft center. 
     
     
       5. The apparatus of  claim 4 , wherein rotation about the rotation axis changes the size of the electrode gap. 
     
     
       6. The apparatus of  claim 1 , the gap range being at least 25 mm. 
     
     
       7. The apparatus of  claim 1 , the electrode gap comprising a maximum value of 98 mm and a minimum value of 63 mm. 
     
     
       8. The apparatus of  claim 1 , the electrode system further comprising a plurality of deceleration electrodes, the plurality of deceleration electrodes being disposed upstream of the exit electrode assembly, closer to the entrance aperture. 
     
     
       9. A system for ion implantation, comprising:
 an ion source, arranged to generate an ion beam; 
 an electrode system, the electrode system comprising a plurality of electrodes to guide the ion beam from an entrance aperture to an exit aperture; and 
 a voltage supply to apply a plurality of voltages to the electrode system, wherein the electrode system further comprises a exit electrode assembly, the exit electrode assembly comprising a first exit electrode and a second exit electrode, separated from the first exit electrode by an electrode gap, wherein the first exit electrode and the second exit electrode are movable with respect to one another so as to change a size of the electrode gap over a gap range. 
 
     
     
       10. The system of  claim 9 , further comprising a motor, the motor being mechanically coupled to the exit electrode assembly and supplying a linear motion to the exit electrode assembly. 
     
     
       11. The system of  claim 9 , further comprising a controller to supply a control signal to adjust the electrode gap, responsive to user input. 
     
     
       12. The system of  claim 9 , wherein the first exit electrode and the second exit electrode comprising a shaft, wherein the shaft comprises a shaft center, and wherein the shaft is rotatable about a rotation axis, the rotation axis being displaced from the shaft center. 
     
     
       13. The system of  claim 12 , wherein rotation about the rotation axis changes the size of the electrode gap. 
     
     
       14. The system of  claim 9 , the gap range being at least 25 mm. 
     
     
       15. The system of  claim 9 , the electrode system further comprising a plurality of deceleration electrodes, the plurality of deceleration electrodes being disposed upstream of the exit electrode assembly, closer to the entrance aperture. 
     
     
       16. The system of  claim 9 , further comprising a substrate stage, disposed downstream to the electrode system, wherein the substrate stage and the exit electrode assembly are arranged to be held at a same voltage. 
     
     
       17. A method, comprising:
 generating an ion beam; 
 decelerating the ion beam in an electrode system, wherein the ion beam is directed to a substrate; and 
 adjusting an electrode gap between exit electrodes of the electrode system, based upon a beam height of the ion beam. 
 
     
     
       18. The method of  claim 17 , comprising adjusting the electrode gap to equal the beam height. 
     
     
       19. The method of  claim 17 , wherein the electrode system comprises an exit electrode assembly having a first exit electrode and a second exit electrode, wherein the beam height comprises a size of the ion beam along a line extending between the first exit electrode and the second exit electrode. 
     
     
       20. The method of  claim 19 , wherein the first exit electrode and the second exit electrode comprising a shaft, wherein the shaft comprises a shaft center, wherein the adjusting the electrode gap comprises rotating the shaft of at least one of the first exit electrode and the second exit electrode about a rotation axis, the rotation axis being displaced from the shaft center.